As a guy who gets paid only because of his computer knowledge, the
following paragraph is a bit of a comfort to me:

One of the many consequences of the exponential power-versus-time
curve in computing, and the corresponding pace of software
development, is that 50% of what one knows becomes obsolete over every
18 months. Unix does not abolish this phenomenon, but does do a good
job of containing it. There's a bedrock of unchanging basics —
languages, system calls, and tool invocations — that one can actually
keep using for years, even decades. Elsewhere it is impossible to
predict what will be stable; even entire operating systems cycle out
of use. Under Unix, there is a fairly sharp distinction between
transient knowledge and lasting knowledge, and one can know ahead of
time (with about 90% certainty) which category something is likely to
fall in when one learns it. Thus the loyalty Unix commands.